
theorem Th1082:
Sum digits(225,10) = 9
proof
  thus Sum digits(225,10) = Sum <%5,2%>+Sum <%2%> by Th1081,AFINSQ_2:55
  .= (5 + 2) + Sum <%2%> by AFINSQ_2:54
  .= 7 + 2 by AFINSQ_2:53
  .= 9;
end;
